This proposal describes the qualifications and experience of the Maternal- Fetal Medicine faculty and research team at the University of Texas Southwestern Medical Center and Parkland Hospital and the facilities and patient population available to them for carrying out clinical protocols to be designed by the NICHD Maternal-Fetal Medicine Units Network. UT Southwestern's Division of Maternal-Fetal Medicine include 11 physicians, 9 of whom are board-certified in Maternal-Fetal Medicine. A total of 6 research nurses experienced in perinatal research lead by a research nurse coordinator with 12 years experience in protocol development and implementation are available for participation in MFM Units Network protocols. A computerized perinatal database that has been operational since late 1982 is a centerpiece in perinatal research team efforts at UT Southwestern Medical Center - Parkland Hospital. The perinatal research team has successfully completed several randomized trials and submitted with this application is an example of such effort in 2,138 women with pregnancy-induced hypertension who were randomized to receive magnesium sulfate or phenytoin for eclampsia prophylaxis during labor. In 1994 there were 13,935 deliveries at Parkland Hospital and approximately 55% were high-risk. Pregnancy complications of particular interest to the MFM Units Network, e.g. preterm birth and gestational diabetes are well represented in the obstetric population at Parkland Hospital. Importantly the maternal-fetal medicine physicians at Parkland Hospital are philosophically committed to rigorous controlled trials intended to objectively evaluate principals of obstetrical care before adoption of these interventions into clinical practice. Other resources brought to the MFM Units Network include support of UT Southwestern's NIH General Clinical Research Center, the Cecil H. and Ida Green Center for Reproductive Biology Sciences and collaboration with the NICHD Neonatal Unit Network through support of the local neonatal network principle investigator. The perinatal research team now described is committed to collaborative participation consistent with the goals of the MFM Units Network.